In vivo detection of liver steatosis in rats based on impedance spectroscopy

Hepatic steatosis is a widespread condition of high prevalence in Western populations, and its asymptomatic nature represents a hefty problem in liver surgery and transplantation. Current diagnostic methods rely mainly on biopsy and blood tests, and are thus time consuming and expensive. Here we report the use of direct impedance measurements on liver tissue as a promising alternative to conventional diagnostic methods in surgery and transplantation. Working on a dual Zucker Fat (ZF), Zucker Lean (ZL) rat experimental model, we show that certain parameters extracted from multi-frequency impedance measurements correlate well with the presence of steatosis and that these results can be adequately approximated with bi-frequency measurements extracting the impedance modulus at 1 kHz and the impedance phase angle at 5.7 kHz. We further support our findings on a theoretical model of tissue impedance, and the simulations carried out suggest a possible mechanism to expound the negative effect of steatosis in post-transplant graft function.